1. Technical Field
The present invention relates to methods and apparatus utilizing Rankine Cycle devices in general, and to those methods and apparatus that utilize Rankine Cycle devices to generate electrical power in particular.
2. Background Information
Marine and land based power plants can produce exhaust products in a temperature range of 350-1800° F. In most applications, the exhaust products are released to the environment and the thermal energy is lost. In some instances, however, the thermal energy is further utilized. For example, the thermal energy from the exhaust of an industrial gas turbine engine (IGT) has been used as the energy source to drive a Rankine Cycle system.
Rankine Cycle systems can include a turbine coupled to an electrical generator, a condenser, a pump, and a vapor generator. The vapor generator is subjected to a heat source (e.g., geothermal energy source). The energy from the heat source is transferred to a fluid passing through the vapor generator. The energized fluid subsequently powers the turbine. After exiting the turbine, the fluid passes through the condenser and is subsequently pumped back into the vapor generator. In land-based applications, the condenser typically includes a plurality of airflow heat exchangers that transfer the thermal energy from the water to the ambient air.
In the 1970's and 1980's the United States Navy investigated a marine application of a Rankine Cycle system, referred to as the Rankine Cycle Energy Recovery (RACER) System. The RACER system, which utilized high-pressure steam as the working medium, was coupled to the drive system to augment propulsion horsepower. RACER could not be used to power any accessories because it as coupled to the drive system; i.e., if the drive system was not engaged, neither was the RACER system. The RACER system was never fully implemented and the program was cancelled because of problems associated with using high-pressure steam in a marine application.
What is needed is a method and apparatus for power generation using waste heat from a power plant that can be used in a marine environment, and one that overcomes the problems associated with the prior art systems.